# list1 = [1,2,3,2]
# a = list1[0]
# for i in list1 :
#     if i > a:
#         a=i
# print(a)


#isinstance

# list2 = [1,2,3,4,"a",1]
# sum = 0
# for i in list2:
#     if isinstance(i,int):
#         sum =sum + i
# print(sum)



# x = 2
# for i in range (2,x):
#     if x % i == 0:
#         print("不是素数")
#         break
# else:
#     print("是素数")



# x = 10 
# sum = 0
# for i in range(2,x+1):
#     for j in range (2,i):
#         if i % j == 0:
#             break
#     else:
#         sum = sum +1
# print(sum)
